Nuclear reactor fuel element assemblies employ grid spacers for maintaining the fuel elements in parallel array. Typically each fuel element assembly in the reactor will employ one or more grid spacers disposed in spaced relation along the length of the assembly, serving to maintain the fuel elements in their correct lateral disposition relative to each other. Grid spacer designs heretofore have essentially comprised a plurality of intersecting members secured together and having a peripheral band for creating a structural member which can accommodate the fuel elements. These structures include springs of the lantern-type design at various of the intersections of the members, which extend into the adjoining fuel openings for coaction with the grid structure to maintain the fuel elements in their desired orientation, especially when the reactor is in operation. The number of springs typically required are usually quite large depending upon the particular fuel design and the overall assembly and construction of such a prior art grid spacer has been relatively complex and expensive from a fabrication viewpoint. Usually, these lantern-type springs have been supported by the grid structure in order to permit them to provide their desired function. Prior art grid spacers of this type may be found in U.S. Pat. Nos. 3,379,618 and 3,654,077.
Another prior art grid structure which includes resilient supports for the fuel elements is disclosed in U.S. Pat. No. 3,833,471. This latter patent, while disclosing the use of spring strip, essentially differs from the present invention in a number of significant respects as will become apparent from detailed reading of this disclosure. The present invention offers advantages over the latter patent which include not only those mentioned heretofore, but also provide for more positive alignment of the strip while allowing greater flexibility to counterbalance the effects of differential thermal expansion. The springs are arranged in alternating directions so that the reaction forces tend to counterbalance each other which in turn minimize the reaction loads on the supporting structure.